Aphids of Southern California

Looking back on the past few months it seems that I have done one of the more detailed and best documented searches for aphids which has been done in this area. It is nothing compared to Aphid Trek's 9,000 slide collection, but the more than fifty species I have found included species apparently never photographed, species apparently unreported in California, and even some which are almost certainly undescribed species.

After getting through so many, I thought it was time to put together one location where I can quickly reference all the aphids I have found in Southern California. I will add on to as I continue to find more. This should be able to serve as a quick reference for anyone trying to identify an aphid they found or looking to find more species.

Given the complexity of aphids I probably have a few incorrect identifications. Most have been confirmed by someone who knows more about aphids than I, but a few I have stubbornly held on to an identification which is not as certain as it should be.

Acyrthosiphon

Acyrthosiphon kondoi:
A common aphid on legumes. It can be separated from pea aphids by inspecting the antenna. The blue alfalfa antenna gradually darken to brown.

Host: I found it on a deervetch (Acmispon sp)

 Acyrthosiphon lactucae:

This is one of the most common aphids in California. However it is surprisingly difficult to find. When I first found it I had to stare at prickly lettuce plants for a good five minutes before I saw it. However once you start to watch for it among the flowers you will almost always find it.

Host: Prickly lettuce (Lactuca serriola) as well as cultivated lettuce

Aphis

Aphis (asclepiadis?)
A difficult to identify aphid which I need to return to in an attempt to get a more certain ID.

Hosts: I found them on Red yucca (hesperaloe parviflora)

Aphis ceanothi
Due to the small number of species of aphids recorded on Ceanothus this seems to be an easily identified species for an Aphis.

Hosts: I found them on (Ceanothus)

Aphis coreopsidis:

These aphids have distinctive antenna which are light at the base then dark, they also have a light head.

Hosts: A very common aphid on Bidens pilosa

Aphis craccivora:

A very common aphid on a wide variety of hosts. Unfortunately not very easily identified from photos due to the large number of black Aphis members.

 Hosts: I have mostly found these on the climbing milkweed (Funastrum cyanchoides) in my yard and on bur clover plants

Aphis (fabae?):

Very difficult to identify. I have never found one which is a solid ID for this species. However I included it since I found some aphids which are probably this species.

Hosts: The aphids I believe are this species were on nightshade and dock (Rumex) plants.

Aphis farinosa:
A rather generic looking green Aphis. On willows there are apparently not many similar aphids though making it reasonably easy to identify.

Hosts: Willows

Aphis gossypii:
One of the most common aphids in Southern California but not particularly easy to identify due to the number of similar Aphis species.

Hosts: I have found it on a huge variety of plants including star jasmine, roses, hibiscus, Bidens pilosa, and Triadica sebifera

Aphis (cytisorum?):
Another challenging to identify black Aphis

Hosts: I found it on Spanish broom(Spartium junceum).

Aphis nasturtii:
Yet another generic green aphid. The siphinculi is significantly lighter than melon aphids or spirea aphids.

Hosts: Primroses, thus far I have only found on Oenothera elata.

Aphis nerii:
This is probably the most commonly found aphids in Southern California. Find a milkweed plant, it almost certainly has loads of this aphid.

Hosts: I have found this only on Asclepias and Funastrum species although it can be found on a great many other plants.

Aphis pentstemonicola:
 Not particularly common but unusually easily identified from photos due to the large dark patches. 

Hosts: I found it on Penstemon grinnellii, although it is likely present on other Penstemons 

Aphis sambuci
Yet another generic Aphis. These seem to be distinctive due to how closely they pack on the stems of elderberries.

Hosts: I found these on blue elderberries, and docks (Rumex)


Aphis sedi:
These are so close to melon aphids that I am not certain I found them. However I have found aphids on a member of the stonecrop which look like melon aphids but have a dark cauda. 

Hosts: I only identified the host plant to the stonecrop family.

Aphis spiraecola:
 One of the most common aphids in Southern California, particularly in hotter months. It is present on a great many plants. On some hosts it is very difficult to separate from A. pomi but on many plants this is the

Hosts:  Seems like they are found on just about anything. Among other plants I have seen them on indian hawthorn. citrus, and Bidens pilosa.

Aphis Sp.
An aphid I found on docks and was never able to find a plausible species level ID for.

Hosts: Dock

Brachycaudus

Brachycaudus cardui:
One of the more recognizable and common aphids.

 Hosts: Many species of thistle.

Brachycaudus helichrysi:
I suspect that I have encountered this species much more as they just look to me like nymphs. Since nymphs are not typically identifiable I likely passed these by. When I found them they were with two Aphis species so I simply did not realize that there was a third species there.


Hosts: I found them on sunflowers, but they are likely to be present on many other plants.

 Braggia

Braggia deserticola
I only found this species because I noticed some ants among the flowers of a buckwheat plant. They hid well enough that I have probably walked past a great many.The really short siphunculi should separate them from other species in the genus.

Host: Buckwheat plants (Eriogonum)

Braggia eriogoni
Another Braggia species which is easy to tell from Braggia deserticola due to the longer siphunculi and white patches.

Host: Buckwheat plants (Eriogonum)

Brevicoryne

Brevicoryne brassicae:

Cabbage aphids are one of the more reported aphids on iNaturalist due to how common and conspicuous they are.

Host: Mustards including wild black mustard and cultivated mustards such as cabbage, kale, and broccoli .

Carolinaia

Carolinaia (setariae?):
The first time I found it I threw away the photos because I thought it was a mummy. Further examination though showed them to be clearly living aphids. The species was previously only reported from Mexico and Brazil but the description seems to match C. setariae.

Host: Grasses,most commonly hiding among the flowers of Polypogon monspeliensis.

Chaitophorus 

 Chaitophorus populicola:
One of the most common aphids on Poplar trees.  Easiest to identify from the winged alate form, but I never seem to find them.

Hosts: Poplar trees

 Chaitophorus sp 1:
 I found some aphids near Jenks Lake which don't seem to fit in any key. They must be an undescribed species.

Hosts: Willows

 Chaitophorus sp 2:
A batch of aphids I found in the Angeles National Forest but have not managed to identify to species.

Hosts: Willows

 Chaitophorus sp 3:
Another batch of aphids I found in the Angeles National Forest but have not managed to identify to species.

Hosts: Willows

 Chaitophorus sp 4:
Some aphids I found in Diamond Bar but have not managed to identify to species.

Hosts: Willows

Diuraphis

Diuraphis noxia:

Russian Wheat aphids are easily identified by what looks like a second tail.

Hosts: Many grasses, I found them on wall barley Hordeum murinum

Dysaphis

Dysaphis apiifolia:

A small aphid resembling an Aphis.

Host: Fennel and other carrot family members.

Eulachnus

Eulachnus (agilis?):

 This is a complicated genus which I need to do some research on. I only have found records of two species in the Eulachnus genus in California. If these are the two species I am finding than this one is E. agilis. Unfortunately it sounds like this genus is a mess, so confirming that will take some work:

Host: Pine trees

Eulachnus (rileyi?):

There is a very common species on pines in Southern California which sure looks like E. rileyi to me. However I have yet to be able to complete a key to identify one of these so given the complexity of the genus it may well be something else.

Host: Pine trees

Essigella

 Essigella (californica?):
Like Eulachnus this is another genus of aphids on pines which I need to give some more thought to.

Hosts: Pine Trees

Eucarazzia

Eucarazzia elegans:
This is an oddball aphid which was relatively easily identified despite the fact I found it on a less than typical host.

Hosts: I found a group of them on a California Fuschia.

Greenidea

Greenidea (ficicola?):
The hairy siphinculi on this species makes it relatively easy tell from other aphids. This is the Greenidea best recorded as being present in California

Hosts: Ficus trees

Greenidea psidii:
The hairy siphinculi on this species makes it relatively easy tell from other aphids. I haven't done enough research to be certain there are not others in the genus, but as best I can tell this one is correct.

Hosts: Melaleuca quinquenervia

Hyperomyzus

Hyperomyzus lactucae:
This is one of the most easily found aphids in Southern California. They are very common on sow thistle (Sonchus) plants which are a very common weed. The problem is that despite being common they are pretty difficult to tell from other members of the genus. In particular Hyperomyzus carduellinus is difficult to rule out. At the moment all the aphids in this genus I have investigated have been either inconclusive or Hyperomyzus lactucae though. So maybe that is the only species we have here.

Hosts: Sow thistles (Sonchus)

Hysteroneura

Hysteroneura setariae
Resembling yet another black Aphis, this is one of the more common aphids on grass. The pale sections on the antenna, tibae and cauda make this surprisingly easy to identify.

Hosts: A wide variety of grasses. I have found this most consistently on Bermuda Grass but it is not uncommon on other species such as Schismus

Illinoia

Illinoia liriodendri
Not a typical aphid of California but I found some on a Tulip Tree in a park.

Hosts Tulip tree (Liriodendron tulipifera)

Lipaphis

Lipaphis pseudobrassicae
A common aphid on many mustard plants, often hiding among flowers. Somewhat resembles cabbage aphids but has less wax.

Mustards, particularly shortpod mustard (Hirschfeldia incana)

Macrosiphoniella

 Macrosiphoniella ludovicianae
A difficult to identify inhabitant of Artemisia plants.

Hosts: I have found them on California mugwort (Artemisia douglasiana), they should be present on other members of the genus.

Macrosiphoniella glabra
Another difficult to identify inhabitant of Artemisia plants.

Hosts: I have found them on taragon (Artemisia dracunculus), they should be present on other members of the genus.

Macrosiphum

Macrosiphum californicum
Unusual for willow aphids that there do not appear to be a ton of look-alikes(or if there are they are currently undescribed)so it is relatively easily identified.

Hosts: Willows

Macrosiphum euphorbiae
If you search for Aphids in Southern California you quickly get tired of seeing yet another potato aphid. They inhabit a great many plants in huge numbers.

Hosts: I have found them on roses, prickly lettuce (lactuca serriola) sow thistles (sonchus), fleabanes (erigeron), orange bush monkeyflowers (mimulus aurantiacus), and white sage (Salvia apiana). Which pretty much means they eat anything.

Macrosiphum gaurae
A large aphid on primroses. Can be separated from M. euphorbiae by the additional dark on the siphinculi.

Hosts: I found it on Oenothera elata, it should be present on other primroses.
Macrosiphum rosae
One of the more common aphids, lots of look-alikes but I belive these can be identified due to the long dark siphunculi.

Hosts: Roses
Macrosiphum salviae
As far as I can tell I am the only one to have reported this aphid in California. The large dark patch on the back may be distinctive.

Hosts: Salvia greggii

Melanaphis

Melanaphis donacis
A common and easily identified aphid on giant reeds.

Hosts: Giant reed, (Arundo donax)

 Metopolophium

 Metopolophium dirhodum
I will have to learn to pay attention to potato aphids on roses to make sure I don't confuse this one. They appear to typically be lighter colored than potato aphids.

Hosts: I have seen rose grain aphids on grasses. Presumably they also can be found on roses.

Mindarus

Mindarus Sp.
Relatively found on white fir plants because of the curling of newly grown in leaves they cause. They proved to be very difficult to get to species.

Hosts: I always found on white fir (Abies concolor)

Myzocallis

Myzocallis longirostris
As best I can tell, this species was apparently previously unreported in California. That means it is pretty likely I misidentified it. It did seem to key out to this species though.

Hosts: Coast Live Oak

Myzocallis punctata
One of the more brightly colored aphids. Supposedly there are some look-alikes but I haven't really researched the genus.

Hosts: Oaks

Myzocallis sp.
A drab aphid which proved incredibly difficult to get to species. I may try again once I finish some microscope upgrades.


Hosts: Oaks

Myzus

Myzus persicae
Green peach aphids, another weedy aphid present on a wide variety of hosts.
Hosts: I most often find these on the leaves of mustard plants. I have also found on Vinca major.

Neophyllaphis

Neophyllaphis (varicolor?)
Before doing this I failed entirely to grasp the transient nature of aphids. When I found this species in August they were ridiculously common. Then they disappeared within a few weeks of my seeing them and I have not seen them again.

Hosts: Afrocarpus falcatus. Although they must go somewhere when it isn't August...

Neosymydobius 

Neosymydobius (paucisetosus?)
I came to the conclusion this is N. paucisetosus, or it seemed to key out correctly but any time a species is previously unphotographed it is hard.

Hosts: Oaks

Neotoxoptera

Neotoxoptera formosana 
Late the last few winters a plague of these descended on my onions. They seem to disappear by late spring.

Hosts: Onions and chives

Pterocomma 

Pterocomma Sp.
Now that I know a bit more about aphids I will have to track down this genus and try again to identify to species. Thus far I have failed to identify one though.

Hosts: Willows

Pleotrichophorus

Pleotrichophorus gnaphalodes
A hairy white aphid which I suspect is rather common and easily identified on California mugwort.

Hosts: California mugwort(Artemisia douglasiana)

Pleotrichophorus oestlundii
A well camouflaged species which can be found on Goldenbush plants.

Hosts: Ericameria

Pleotrichophorus stroudi
Another species of green Pleotrichophorus which are somewhat difficult to identify.

Hosts: Ericameria

Pterocallis

Pterocallis alni
A small aphid resembling a chaitophorous species. Sometimes it is present in large numbers on alders in canyons. I found it on an alder in a park. The dark spots on the legs make it straight forward to identify.
Hosts: Alders

Rhopalosiphum

Rhopalosiphum (maidis?)
I found some grass aphids and completely failed to key them out. Looking at pictures of R. maidis it seems like they must be R. maidis though.

Hosts: I found it on a grass in the genus Phalaris, but it should be on many other types of grass.

(Rhopalosiphum nymphaeae?)
Often I find aphids after I get home. This aphid hiding on duckweed was one of them. A shame I didn't see it in the field or I would have got better photos.

Hosts: Duckweed

Rhopalosiphum padi
As far as I can tell this is one of the more common and easily identified of aphids on grass. The rust color around the siphunculi stands out a lot.

Hosts: Grasses and similar monocots. Hordeum murinum and Iris are two examples.

 Sarucallis

Sarucallis kahawaluokalani 
In the running for the hardest aphid name to say. Luckily it is about the easiest aphid to find and identify. Find a crape-myrtle tree. This isn't hard, you probably see a hundred trees a day as they are such commonly planted street trees. Look under a couple of leaves. There, you found it.

Hosts: Crape myrtle (Lagerstroemia indica)

Schizolachnus

Schizolachnus sp.
Did I mention pine aphids were hard?

Hosts: Pines

Sipha

Sipha flava 
Much less common than Sipha maydis, but also occassionally found on grasses.

Hosts: Grasses.

Sipha maydis 
A recent introduction to Southern California which is now one of the most common aphids on grasses.As it is so common on many of the most invasive grasses this one may actually be having a real ecological impact.

Hosts: Grasses. I have found it on many common grasses such as Hordeum murinum Avena barbata and Bromus diandrus

Sitobion

Sitobion avenae
There are two common dark green aphids on grasses. This one can be separated from S. fragariae because of the long cauda.

Hosts: I have found on Avena fatua should be present on other grasses.

Sitobion fragariae 
Another generic green aphid. Commonly found hiding among grass seeds. Can be separated from S. avenae because of the short cauda compared to the siphunculi.

Hosts: I have found on Hordeum murinum should be present on other grasses.

Stegophylla

Stegophylla (essigi?)
This aphid can be commonly found on live oak trees by looking for either white fluff on the leaves or folded up leaves. I haven't been able to solidly confirm species, but it is probably S. essigi.

Hosts: Oaks

Tamalia

Tamalia Sp. 
These are what make the red galls on Manzanita plants. Almost all the Tamalia on iNaturalist are marked as Tamalia coweni. In parts of the state this might be accurate, but I suspect many are other members of the genus in many of those galls. If you find these, try to get a picture of the actual aphid, not just the gall.
Hosts: Manzanita

Therioaphis

Therioaphis trifolii 
These have been present in my back yard for some time. They hide under clover leaves. Despite a lot of looking I have yet to see any on clover plants not in my yard.
Hosts: Clover

Tinocallis

Tinocallis saltans
Surprise! Another aphid!

Hosts: Siberian elm, Ulmus pumila.

Tinocallis (ulmiparvifoliae?)
This is a common aphid in urban areas. It only has a winged form. I believe the bumps and markings on its head and thorax make it T. ulmiparvifoliae but I don't know the genus well.

Hosts: Elms. The type you usually find in parks in Southern California. 

Uroleucon

Uroleucon ambrosiae
One of the red aphids that can be found on top of mule fat plants. Apparently there is some controversy as to whether this species actually inhabits plants other than ragweed, but it sure seemed to key out to this.

Hosts: Mule Fat

Uroleucon erigeronense
Looking suspiciously like potato aphids, these are supposed to be common on plants of the sunflower family.


Hosts: Telegraphweed (Heterotheca grandiflora)

Uroleucon picridis
Apparently both U. picridis and U. sonchi live on bristly ox tongue. Every time I find them though they seem to key out to U. picridis.

Hosts: Bristly ox tongue (Helminthotheca echioides)

Uroleucon sonchi 
There are supposed to be a great many Uroleucon species present on sow thistle. I often think I found a new one of them. Thus far every single one has been U. sonchi on closer examination.

Hosts: Sow thistles.

Uroleucon Sp. 
This species was very common northwest of Palm Springs on Brittlebush plants. At the time I was not up to the task of identifying it beyond genus but I will have to try again next spring. 

Hosts: Encelia farinosa

Wahlgreniella

Wahlgreniella nervata
These have been on the tree in my front yard for a couple years now. They seem to come in waves where sometimes I can hardly find them and other times they are everywhere. Somewhat unusual in having two color forms.

Apparently species are poorly understood in this genus so the identification is somewhat tenuous.

Very common on Arbutus trees and can occasionally be found on roses.

Labophot Microscope

I noticed a long time ago that the fact I am an engineer shows in my iNaturalist submissions. I have always managed to make it an excuse to play with some gadget or another. So of course, I have wanted a phase contrast microscope since I first learned it was needed to identify many aphids.

Reading up a bit on the topic it was clear that there are two reasonable routes there. First is the low end modern microscopes. Trinocular phase contrast microscopes from Omax, Amscope, or National Optical are available and probably good for any purpose I am likely to use them. The other option is 1980s era entry level research microscopes. Of those the Olympus BH2 and Nikon Labophot seem the most popular. Both these routes seem similarly priced and at least on paper give similar function.

After giving it some thought, going the old microscope route makes a lot more sense to me. Having an above average ability to tinker, it just seems like I can squeeze more out of them than the average user. Also, the microscope has survived thirty plus years and has a large market for used parts so it seems like I should be able to keep one running indefinitely.

After shopping around, I picked up a Nikon Labophot a condenser, and a 10x objective off of ebay. This seemed to be the cheapest way possible to phase contrast. While the Olympus BH2 is similar price, it seemed that condensers with phase contrast, bright field, and dark field as well as trinocular heads are half the price on the Labophot system. Also, the better objectives on the Nikon system can be directly mounted to a camera and used with my stackshot setup.

I was too cheap to get a trinocular head initially. I figured I would just get one a few months in the future. That quickly drove me nuts. I work by creating photos which are identifiable. Having a device which could identify species but could not share that information just wouldn't work.

First I tried using my camera by looking into the eyepiece with my macro lens. This was a horrible disaster, completely unsharp images. Then I tried using my cell phone to take images. A step up, but still frustrating:

That image showed some details correctly, but compared poorly to the Miutoyo 5X and stackshot setup I was using previously. That setup gave somewhat less detail than the cell phone in the objective, but certainly produced cleaner pictures:

After a few days of thinking about the problem, I realized it was possible to take the head off the microscope and project an image above it. Then, if I held the camera there without a lens I could see something. The first try was a failure, but then I realized that a stack of extension tubes allowed me to hold the camera still:

This did the trick! Now I can take reasonably good photos on the microscope. It even allowed me to make focus stacks by taking a couple photos of an area I am interested in. Even for dark field images it appears to be stable enough to work with the 10X objective:

With phase contrast and a little focus stacking though, it is pretty clear I finally have the magnification to identify most aphids or similar size arthropods. This is a lot more detail on hairs and other small features than I previously had. Eventually I will get a 20X, 40X, and 100X objective to go with the 10X, but this setup does appear to work well as is:

Now I am questioning whether I even want to bother with the trinocular head. A cheap adapter or two could get me from the 48.5mm dovetail connector on the microscope to the setup I am holding on the microscope right now.

Scale Bars

I have long wanted to put scale bars on pictures. They just make them seem more scientific. When it comes to more difficult species to ID they can even be pretty important in being able to get an ID from a photo. With a scale bar it is even possible to put the picture in photoshop, set the scale, and measure out lengths of various details such as antenna length in the photos.

Getting them on images with a macro lens is a bit of a pain though. The scale changes as the image focus changes. In theory it should be possible to take the information in the photo about the lens focus at the time of the photo and convert it to a scale, in practice it is difficult though. At a minimum it takes a bit of scripting, and from what I have read the accuracy of the lenses is not good enough to get particularly accurate.

With a microscope objective it is comparatively easy. As I have it set up my Mitutoyo 5X Objective is either at 3X or 5X magnification. So, all I need do is figure out the dimensions of one pixel in each scenario and make Photoshop add a scale bar. To that end I bought a microscope calibration slide and imaged it at 3X and 5X.

After doing this, I realized that I take a majority of my photos of insects with 1X magnification by putting the macro lens at minimum focus. By taking a photo of the calibration slide at 1X magnification, it is possible to add a scale bar to any photo which was taken at minimum focus distance. Technically this would be possible at any magnification, but 1X magnification is the only magnification I can quickly and accurately reproduce since it is the minimum focus distance.

That was the easy part. Even once I figured out the overall idea, turning this into a practical method took some time. First, I needed to measure the scale bar in Photoshop by going to Image > Analysis > Ruler Tool . That gave me the width of the scale bar in pixels. With the length of the 1 mm scale in pixels I was able to calculate the width of a single pixel in microns.

I was then able to set the scale such that I could measure any dimension in correct microns by going to Image > Analysis > Set Measurement Scale > Custom and setting it so one pixel was the correct number of microns. Then by going to Image > Analysis > Place Scale Marker I could make a 1mm scale bar. Unfortunately it gave a scale bar with a ridiculous number of significant digits and units in microns. Luckily with the text edit I was able to set it to 1mm.

Now I had my first scale bar!

After making about ten of these, I realized that this was just way too much work to fit into my workflow. It needed to be automated!

First I read up on Photoshop actions. By making a new action and by pressing record when I made the scale bar I was able to turn the process of making a scale bar into pushing one button. Then I made another action which recorded the process of saving as a jpg. Now I just needed to load the photo into photoshop and hit two buttons and the whole process would just work.

Still too much work.  Then I learned that by going to File > Automate >  Batch I could run the action to add a scale bar to every photo which is open. So now all I do is load all the files to get a scale bar, tell it to put a scale bar on every photo then tell it to save every photo. I will have to turn it all into one action one of these days, but it is finally practical to insert into my workflow.

If you are trying this there are a few traps to watch out for. First, the pixel size must be unchanged since the photo was taken. If the photo was compressed when you exported from Lightroom, or saved in some other software then all your scale bars will be wrong. Also, it is easy to put a photo into Photoshop which was not at 1X magnification. Any of those photos will have a wrong scale bar.